1. Field of the Invention
The present invention relates to a liquid processing apparatus used for applying a predetermined liquid processing or drying processing to various substrates such as a semiconductor wafer and a LCD substrate.
2. Description of the Related Art
In, for example, the manufacturing process of a semiconductor device, used are a wafer cleaning apparatus for cleaning a semiconductor wafer (wafer) used as a substrate with a predetermined chemical liquid or a pure water for removing from the wafer the contaminants such as particles, an organic contaminant and metallic impurities, and a wafer drying apparatus for removing liquid droplets from the wafer by using an inert gas such as a nitrogen gas (N2 gas) or an IPA vapor having a high volatility and a high hydrophilic nature so as to dry the wafer.
Known are a single wafer type cleaning apparatus or drying apparatus in which the wafers are processed one by one and a batch type cleaning apparatus or drying apparatus in which a plurality of wafers are housed in a wafer cleaning chamber or a wafer drying chamber for processing these wafers in a batch system.
Known as a single wafer cleaning apparatus is an apparatus called scrubber, in which a wafer is held at its peripheral portion or back surface and a process liquid is spurted to the front and back surfaces of the wafer while rotating the wafer within a horizontal plane, or a brush or the like, which is kept rotated, is scanned on the front surface of the wafer.
However, where a cleaning treatment is performed with the wafer held horizontal, a problem is generated that, when the wafer is rotated after the cleaning treatment for removing the cleaning liquid attached to the wafer, it is difficult to remove the cleaning liquid satisfactorily. Also, where the cleaning treatment is performed with the wafer held horizontal, the inner volume of the cleaning process chamber is increased in general, with the result that the amount of the exhaust gas is increased when the cleaning process chamber is exhausted. Therefore, the temperature of the chemical liquid used tends to be lowered, leading to an additional problem that it is rendered difficult to use a chemical liquid of a high temperature. Further, where the cleaning process chamber is of a hermetic structure for the control of the atmosphere, another problem is generated that the control program for controlling the opening-closing mechanism of the cleaning process chamber and the delivery mechanism to the cleaning process chamber of the wafer is rendered complex. In addition, where the wafer is disposed horizontal, it is difficult to superpose a plurality of wafers one upon the other in a vertical direction for processing the wafers.
On the other hand, a wafer cleaning apparatus 500 shown in, for example, FIG. 31 is known as a batch type cleaning process apparatus. As shown in the drawing, the wafer cleaning apparatus 500 comprises a process chamber 502 forming a wafer cleaning chamber 501. A rotor 505 arranged to be capable of holding a wafer W and rotatable is movable into and out of the process chamber 502 through a wafer delivery port 503 formed forward of the process chamber 502. Delivery of the wafer W can be performed between the rotor 505 and wafer chucks 509a, 509b of a transfer arm, with the rotor 505 moved forward of the process chamber 502. A reference numeral 507 shown in FIG. 31 represents a driving mechanism for moving back and forth and rotating the rotor 505. A reference numeral 508 represents a rotary shaft. A reference numeral 504 represents a lid of the process chamber 502. Further, a reference numeral 506 shown in FIG. 31 represents a holding member of the rotor 505.
However, in the wafer cleaning apparatus 500 shown in FIG. 31, it is necessary to control the operation of the apparatus 500 in a manner to prevent the collision between the wafer chucks 509a, 509b and the holding member 506 of the rotor 505, leading to a problem that the operating program is rendered complex.
In recent years, the wafer size is increased from 200 mmÅ to 300 mmØ in accordance with progress in the miniaturization, degree of integration and mass production of semiconductor devices. A container capable of housing wafers in a vertical state was used for storing and transferring the wafers when it comes to the wafers of 200 mmØ. However, a container housing the wafers in a horizontal state has come to the used when it comes to the wafers of 300 mmØ because the wafer is large and heavy.
Even where the wafers are transferred in a horizontal state, it is desirable to carry out the cleaning treatment itself of the wafers, with the wafers held substantially vertical as in the prior art. Under the circumstances, it is necessary to arrange, for example, a posture changing mechanism for changing the posture of the wafer between the horizontal state and the vertical state in the conventional apparatus in which the wafers were held substantially vertical for the transfer including the wafer cleaning apparatus 500 shown in FIG. 31. As a result, problems are generated that the transfer mechanism of the wafers is rendered complex and that the wafers tend to be contaminated and broken because the number of times of transplanting the wafers among the mechanisms handling the wafers is increased.
It should also be noted that, if the mechanism and member of each section handling the wafers is rendered bulky to conform with the size of the wafer without changing the construction of the conventional cleaning process apparatus, it is unavoidable for the entire cleaning process apparatus to be rendered bulky. Under the circumstances, it is highly desirable to improve the construction of the apparatus so as to suppress the enlargement of the apparatus as much as possible. It is also highly desirable to suppress the enlargement of the cleaning process apparatus in respect of the single wafer cleaning process apparatus.